Proponents of San Francisco's Proposition F insist that their measure is all about "creating dialogue" around the way that San Francisco uses water. They point to San Francisco's low water-recycling rates and poor rainwater-capture systems as a reason why this measure should pass.

If Proposition F was actually about these things, we'd be inclined to agree with them.

But voters shouldn't be fooled. Proposition F is the same old fight about draining Yosemite's Hetch Hetchy reservoir, a major source of water for San Francisco and other Bay Area cities.

The proponents keep losing this fight when they're honest about what draining Hetch Hetchy really means - it's a project that would cost up to $10 billion and would destabilize the water supply for 2.4 million people - so they've dressed it up a bit.

Proposition F requires city officials to create a two-phase plan for the feasibility of draining the reservoir and finding alternative sources of water and power to replace it. Then officials would need to craft this plan into a charter amendment - presumably for a vote in 2016.

How thoughtful of them. Never mind the fact that none of this is practically, politically or financially possible since the "drain Hetch Hetchy" movement has been a political nonstarter for decades. It doesn't make sense environmentally, either, to eliminate a system that produces clean power and delivers high-quality water to 2.4 million people through the force of gravity. The demands on water and power are only to intensify with climate change and population growth.

Another point to consider: Any alternative is going to have its own environmental cost.

No, the proponents of Proposition F want voters to waste $8 million of taxpayer money on this plan anyway, because they're convinced that somehow, some way, their fanciful vision of restoring a beautiful open valley in Yosemite can triumph over the real-world considerations of the 21st century.

San Francisco's voters need to convince them otherwise. Proposition F is a misleading measure that will squander taxpayer money. Vote no on Prop. F.